Relation Between Aqua-regia Extractable Heavy Metals in Soil and Manihot utilissima Within a Municipal Dumpsite

摘要

The relation between aqua-regia extractable heavy metals in Manihot utilissima grown in a municipal dumpsite in Nigeria was investigated. Analysis has revealed significantly higher levels of Cd, Cr, Fe, Mg and Pb in the crop plant and soil from the dumpsite than values recorded fro the background soil (control). Arsenic, which was absent in the soil and plant from the background soil, was detected in soil samples from the dumpsite but not accumulated by the cassava plant cultured in the waste-dump. Heavy metals levels in soil and plants also varied with the sampling grids (locations). However, there was no clear relationship in heavy metals concentration between the cultured plants and corresponding soil from the dumpsite. Although, the levels of (Cd, Cr, Pb) detected in soil and Manihot utilissima are within the regulated limits, the deterioration of the dumpsite soil and environs ecoquality is desirable due to daily input of wastes and sludge. Therefore consumption of crop plants grown in dumpsites may be of serious health risk with the presence and plausible accumulation of metals such as Pb, Cr, Cd and As in the soil and plant. The frequency distribution characteristics and relative standard deviations were studied.